the damage area would better be presented with the pertinent measurements in the projectile (the diamter in an arrow or arrowhead or javelin or spearhead, etc, the diameter in a bullet or pellet, etc. and so on)

The Roman army found that their pila were pretty effective at close range

Wouldn't that make it a melee weapon?

Quote:

Originally Posted by Poly

Peltasts were effective light troops used by many Greek city states as light troops, just as effective as archers

Where peltasts used in the role you would find archers? Or they were meant for close quarters combat? That maks a large difference on whether you could consider them melee or missile

Quote:

Originally Posted by Poly

A hand grenade is a missile weapon, hand thrown and pretty damn effective in certain circumstances (albeit with an explosive core)

The power of a hand grenade comes from its ability to explode, it is often hand thrown because that is the easiest way to keep the explosion away from the person employing it, however scenarios can exist where the weapon is equally lethal without it being thrown (it can be dropped on the target, it can be tied to an animal before making the animal run into the target, etc.)

Quote:

Originally Posted by Poly

common sling is cheap and deadly (OK it is not exactly hand thrown but doesn't seem to fit any of your categories)

I would say it falls under "Handheld with mechanical trigger"... However I want record-braking missile weapons...